Raise boring machine

ABSTRACT

A raise boring machine for producing a raise of circular cross section has a main frame with a rotating drum which has two rotating tangentially cutting heads. Three wall engaging shoes are suspended in rods in toggle arrangements and they are biased outwardly against the wall of the raise by means of spring devices braced between the shoes. By this arrangement these shoes guide the machine by sliding on the wall during a cutting advance of the main frame effected by means of six advance jacks connected between the main frame and a rear anchoring frame. During the time that the anchoring frame is released from the raise and pulled forward by the advance jacks, however, the same shoes hold the main frame firmly in the raise as a result of the action of the toggle joints. Steering is effected by moving the rear portion of the main frame sidewise in the anchoring frame in any desired direction.

United States Patent Lauber et al.

1 51 Oct. 3, 1972 [54] RAISE BORING MACHINE [72] Inventors: ErnstAbraham Lauber, 8 Meisenweg, 3600 Thun, Switzerland; Pieter Barendsen,l2, Ejdervag, 130 10 Ektorp, Sweden 221 Filed: Nov. 9, 1970 [21] Appl.No.: 88,069

52 US. (:1. ..299/31, 175/94, 299/10 51 1m. (:1 ..E01g 3/04 [58] Fieldof Search ..299/31, 10; 175/94 [56] References Cited UNITED STATESPATENTS 2,756,037 7/1956 Kirkpatrick ..175/94 x R24,965 4/1961Kirkpatrick ..299/31 3,486,572 12/1969 Hamilton et al. ..299/31 x3,354,969 1 H1967 Ebeling 175/94 3,061,287 10/1962 Robbins ..299/313,345,108 10/1967 Newman et a1 ..299/31 Primary Examiner-Ernest R.Purser Attomey-Munson & Fiddler ABSTRACT A raise boring machine forproducing a raise of circular cross section has a main frame with arotating drum which has two rotating tangentially cutting heads. Threewall engaging shoes are suspended in rods in toggle arrangements andthey are biased outwardly against the wall of the raise by means ofspring devices braced between the shoes. By this arrangement these shoesguide the machine by sliding on the wall during a cutting advance of themain frame effected by means of six advance jacks connected between themain frame and a rear anchoring frame. During the time that theanchoring frame is released from the raise and pulled forward by theadvance jacks, however, the same shoes hold the main frame firmly in theraise as a result of the action of the toggle joints. Steering iseffected by moving the rear portion of the main frame sidewise in theanchoring frame in any desired direction.

17 Claims, 8 Drawing Figures PATENTEflncr 3 m2 3.695.718

sum 1 or a I N NNNKVAy/W/VWAV/WW/W/V v yN/QXAY AYAXAY INVENTORs ERNSTABRAHAM LAUBER and PIETER BARENDSEN MUNSON & FIDDLER PATENTEDnms m2SHEEI 2 BF 8 ERNST ABRAHAM LAUBER and S. R O T m V N 3 D1 m R A B R E TE I P By MUNSON & FIDDLER PATENTEB m3 m2 SHEET 3 0F 8 Fig- .3

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ERNSTABRAHAM LAUBER and PIETER BARENDSEN IN VENTOR S MUNSON & FIDDLERPATENTEDncI 3 I972 SHEET 5 BF 8 ERNST ABRAHAM LAUBER and PIETERBARENDSEN INVENTORS 7 B3 MUNSON & FIDDLER PATENTEDncrs I972 SHEET 8 OF 8mm QR mm @m mm *m Wm Nm INVENTORS ERNST ABRAHAM LAUBER and PIETERBARENDSEN MUNSON & FIDDLER PATENTEDBBT 3 I SHEET 7 [IF 8 ERNST ABRAHAMLAUBER and PIETER BARENDSEN IXVENTORS HY MUNSON & FIDDLER P'A'TENTEDumsI972 SHEET 8 [IF 8 ERNST ABRAHAM LAUBER and PIETER BARENDSEN 1 AW '5' NT0165 BY MUNSON & FIDDLER RAISE BORING MACHINE This invention relates toa raise boring machine for producing a vertical or inclined raise ofcircular cross section.

In connection with raise driving machines, there is a security problemwhich does not appear in connection with prior art tunneling machinesfor producing horizontal or nearly horizontal circular tunnels; namelythe risk of the falling backwards of the machine in the tunnel.

It is therefore an object of the invention to provide a raise drivingmachine which is always secured in the tunnel even if the power systemfails. In accordance with the invention there is provided a raisedigging machine for producing a raise of circular cross section,comprising a main frame, a drum member rotatably mounted in said mainframe for rotating about a central longitudinal axis of the machinewhich axis normally coincides with the axis of the raise being driven,motor means for rotating said drum member, a number of cutter headsmounted on the drum member for cutting in the face of the raise, anumber of wall engaging shoes mounted to said main frame so as to bemovable radially thereto, means arranged to bias said shoes against thewall of the raise being driven, obliquely arranged struts pivotablymounted to said main frame with their upper ends and pivotably mountedto said shoes with their lower ends so as to prevent the shoes fromsliding rearwards by pressing them against the wall of the raise butpermitting the shoes to slide forwards, an anchoring device movable withrespect to said main frame and arranged to be immobilized in the raise,and power means for moving one of the main frames and the anchoringdevice longitudinally of the raise relative to the other.

The invention will now be described with reference to the accompanyingdrawings in which a preferred embodiment of the invention is shown byway of example.

In the drawings:

F IG. 1 is a side view, partly in section on line 11 in FIG. 2, of araise boring machine in a vertical raise,

FIG. 2 is a fragmentary cross section substantially on line 22 in FIG.1,

FIG. 3 is a fragmentary cross section on line 3-3 in FIG. 1,

FIG. 4 is a fragmentary cross section on line4-4 in FIG. 1,

FIG. 5 is a developed fragmentary view taken as indicated by the line 55in FIG. 2,

FIG. 6 is a fragmentary circuit diagram of the hydraulic system foradvancing and steering the raise riving machine shown on FIGS. 1 4, and

FIGS. 7 and 8 are side views of a vehicle for launching and transportingthe raise driving machine shown on FIGS. 1-5.

The raise boring machine has a main frame generally indicated as 11. Adrum 12 is journalled in the main frame 11 by means of a roller bearing13. The left half of the drum 12 is shown in section in FIG. 1 but theright half in view. Three motor and gearing units 14 rotate the drum 12by means of spur gears 15 which mesh with a ring gear 16 on the drum. Inthe drum 12 are two identical cutting devices l7, 18 mounted, eachcomprising a motor portion 19 and a reduction gearing portion 20 forrotating a cutter head 21, 22 with detachable cutters 23 which havesintered carbide hard metal inserts. The interior parts of the cuttingdevices are removed in FIGS. 2 and 3 and, for clarity, the sections oftheir housings are shown circular in these figures although the circularhousings should be elliptical in a plane cross section. The cutter heads21, 22 work on an undercutting principle which is described for instancein Wohlmeyer US patent 2 758 825 and which will therefore not bedescribed here.

Three triangular and arc-formed wall engaging guide shoes 24, 25, 26 areguided by means of guide surfaces 27 sliding on guide members 28 on themain framel 1.

As shown in FIGS. 3 and 5 there are jacks 29, 30 31 universallypivotally connected between the shoes 24, 25, 26 so as to urge the shoesoutwardly against the wall of the raise by the action of springs 32inside the jacks. The shoes are suspended in the main frame by six rods33, 34, 35, 36, 37, 38 each rod connected between one of the shoes andthe main frame by means of ball joints, the rods providing togglejoints. The jacks 29, 30, 31 press the shoes 24, 25, 26 outwardly sothat the main frame 11 is guided by the shoes sliding on the wall of theraise when the main frame is being advanced. The toggle joints preventautomatically the shoes 24, 25, 26 and thereby also the main frame 11from sliding backwards. When, however, backward movement is wanted, thejacks 29, 30, 31 can be retracted hydraulically to withdraw the shoes24-26 from the wall so that the toggle joints will not actuate the shoes24-26.

Three rectangular rear wall engaging shoes 39, 40, 41 together withthree jacks 42, 43, 44 form an anchoring frame generally denoted 45. Thejacks 42, 43, 44 are connected between the shoes 39, 40, 41 by means ofball joints, and they are biased to retract by means of springs 58, butthey extend upon hydraulic actuation. The rear portion of the main framehas three double acting hydraulic steering jacks 46, 47, 48, each havingtwo piston rods all of which referred to as 49. The main frame 11 isguided by means of universally pivotably mounted end parts on the pistonrods 49 freely sliding on guide surfaces 50 on the shoes 39, 40, 41.Steering is effected by moving the rear portion of the main frame 11sidewise in the anchoring frame 45 in any desired direction, therebycausing the longitudinal axis of the main frame 11 to deviate from thelongitudinal axis of the raise. With the anchoring frame 45 rigidlyclamped to the raise, the main frame 1 1 can be advanced with its frontshoes 24, 25, 26 sliding on thewall of the raise by means of six thrustjacks or advance jacks 51-56 pivotably connected between the main frame11 and the shoes 39, 40, 41 of the anchoring frame 45. During an advanceof the main frame 11, the drum 12 is rotated in the main frame and thecutter heads 21, 22 are also rotated so that the cutter heads cuttangentially in the face of the raise in screw-formed orbital paths. Thesliding connections 49, 50 between the steering jacks 46-48 on the mainframe 11 and the shoes 39-41 of the anchoring frame 45 transmit thereaction torque resulting from the rotation of the drum 12 to thesefirmly braced shoes 39-41. Non-illustrated guide plates are arranged toguide through the machine, the rock fragments cut away and broken awayby the cutters 23 of the cutter heads.

When the advance jacks 51-56 have been fully extended, the anchoringframe 45 is loosened from the wall of the raise and advanced rapidly bymeans of the advance jacks 51-56, the main frame 11 being held by meansof its shoes 24-26 which are now braced rigidly against the wall of theraise by means of the toggle rods 33-38. The anchoring frame 45 is againbraced and a new slow advance step can start. In FIG. 5, there areillustrated the two advance jacks 51, 52 which are connected to the shoe39; the left jack 51 is shown retracted and the right jack 52 is shownextended. The shoe 39 is in the figure shown in two positions, theposition of the left half of the shoe corresponding to the retractedpositions of the advance jacks and the position of the right halfcorresponding to the extended position of the advance jacks.

A non-illustrated bottom power and control station is located so as tobe protected from the rock fragments falling from the machine. Anon-illustrated laser and a non-illustrated television camera arearranged to permit the operator to control the machine in safety fromthe bottom station. Hydraulic and electric power lines and suitableelectric lines for controlling various solenoid valves at the machinelead from the bottom station to the machine. All the electric andhydraulic lines are covered in a common non-illustrated protectingplastic cover which is attached to a steel rope 59 which in turn isattached to the hang wall of the raise by means of support pulleys androck bolts.

In FIG. 6, there are illustrated the advance jacks l-56, the jacks 29-31connected between the guide shoes 24-26, the jacks 42-44 of theanchoring frame 45 and the steering jacks 46-48 on the main frame 11. Alow pressure supply pump 61 supplies fluid from a tank 62 to three highpressure pumps 63, 64, 65 which are situated on the bottom station.Reference numeral 66 denotes a counter-pressure valve. The pump 63supplies pressure fluid to the double-acting advance jacks 51-56 througha flexible supply conduit 67 and a solenoid valve 68. The valve 68 has aposition for effecting extension of the jacks, a position for effectingcontraction of the jacks and a position for locking the jacks. Alimiting device shown as a restrictor 69 controls the speed of extensionand retraction of the advance jacks. The pump 64 supplies pressure fluidthrough a flexible branched supply conduit 70 to the gripper jacks 42-44of the anchoring frame 45 so as to extend these jacks. A fluid dividerassembly in the form of three mechanically interconnected motors 71, 72,73 in the supply conduits of the jacks 42, 43, 44 ensures that the threejacks move conjointly. When necessary, the jacks 42-44 can beindividually adjusted or completely retracted by means of three solenoidvalves 88, 89, 90. By means of the pump 65, the jacks 29-31 of the mainframe 1 1 can be supplied with pressure fluid through a supply conduit74 so that these jacks 29-31 retract.

For security, an electric motor 75 driving the pump 65 has its powercircuit connected over a relay 76. The actuacting circuit for the relay76 includes three pressure actuated switches 77, 78, 79, each connectedto one of the jacks 42-44, respectively. Therefore, the motor 75 canrotate the pump 65 only when there is full pressure in all the jacks42-44; that is to say, the shoes 24-26 of the main frame 1 1 can bereleased only when the anchoring frame 45 is held firmly by its shoes39-41.

If, however, the pressure in the jacks 42-44 would drop suddenly whenthe jacks 29-31 are under pressure, for instance if the supply hose 70breaks a motor 80 will immediately open a check valve 81 through whichthe jacks 29-31 and the supply conduit 74 will drain. As a result, thesejacks 29-31 will therefore immediately force the shoes 29-31 of the mainframe against the wall of the raise and toggle rods 33-38 will apply anadditional outwardly directed force to the shoes so as to secure themachine in the raise.

A sequence valve 82 is arranged to permit pressure fluid to flow fromthe supply conduit 70 to a supply conduit 83 of the steering jacks 46-48only when there is full pressure in the jacks 42-44 of the anchoringframe 45; that is to say, steering is permitted only when the anchoringframe is firmly braced to the wall of the raise. The three steeringjacks 46-48 can be connected in series through three solenoid valves 84,85, 86 having three positions each; the positions of each valve arereferred to as positions a, b and c and represented by the correspondingsquares a, b, c of the symbol of the valve. A solenoid valve 87 having aclosed and an open position is connected in parallel with the valve 85.Since the valves 84-86 are not quite leak proof, there are pairs ofpilot actuated check valves 91 connected in the conduits between thesteering jacks 46-48 and the valves 84-86 so as to positively lock thejacks except during steering movement. The jack 47 has half the pistonarea of the jacks 46, 48 which are identical. When driving inclinedraises, the machine is located so that this jack 47 is horizontal andthe shoe 41 connected to this jack engages the hang wall of the raise.

When it is desired to move the rear portion of the main frame 11 upwardsin FIG. 6 (towards the hang wall in the case of an inclined raise), thevalve 85 is maintained in its illustrated closed position b, the valve84 is shifted into position 0, and the valve 86 is shifted into positiona. Now, when the valve 87 is opened, the cylinders of the steering jacks46, 48 and thereby the rear position of the main frame 11 are movedupwards in FIG. 6, the end portions of all the piston rods 49 of thejacks 46-48 sliding on the guiding surfaces 50 of the shoes 39-41. Inthe same way, the valve 87 is used also for moving the rear portion ofthe main frame 11 downwards in FIG. 6, the valve 84 being in position aand the valve 86 being in position c.

For moving the rear portion of the main frame 11 to the right in FIG. 6the valve 87 is closed and the valves 84 and 86 are shifted intopositions a. The movement starts when the valve 85 is shifted intoposition 0. Since the angles between the steering jacks are 60 and theguiding planes 50 are perpendicular to the respective steering jack, theresulting movement of the rear portion of the main frame 11 will bestraight to the right in FIG. 6 because it results from the movement ofthe piston rods 49 in the cylinders of the steering jacks 46-48 and fromthe sliding movement of the end portions of the rods 49 on the guidingplanes 50. For moving the rear portion of the main frame 1 1 straight tothe left in FIG. 6, the valve 85 is shifted into position a, the valves84 and 86 being in positions 0.

As described, the rear portion of the main frame 11 can thus be moved inone direction by means of the valve 87 and in a direction perpendicularthereto by means of the valve 85 notwithstanding there are only threesteering jacks.

For starting a raise, there is used a launching vehicle shown on FIGS.7-8. The vehicle has an undercarriage 100 movable on two steerable pairs101 of wheels at the front and two rear pairs 102 of wheels. Theundercarriage has two rigid side plates 103-each with a row of holes104. An outer tube 105 is mounted on the undercarriage so as to bepivotable on a transverse shaft 06 by means of two hydraulic jacks 107which are pivotably mounted between the tube 105 and the undercarriage100. Inside the tube 105 there is arranged another tube 108 withcircular cross section. Four hydraulic power jacks 109 are arranged toextend and retract telescopically the tube 108 in the tube 105. Theraise driving machine shown on FIGS. 1 -5 can be placed inside the tube108 which can be considered as a shell for the machine. The cutter heads21, 22 of the machine can be seen in FIG. 8', in FIG. 7, however, themachine is not shown at all. In FIG. 8, the telescoping tubes 105, 108are shown in a retracted vertical transporting position. This positionis indicated in FIG. 7 by a dashand-dot line 110. In FIG. 7, the tube105 is tilted about the shaft 106 and locked to the side plates 103 bymeans of a pair of lock pins 111. At the desired starting point of theraise, a guiding ring 112, adapted to suit the forward end of the tube108, has been fixed to the roof by means of concrete indicated at 113and a number of rock bolts 114. i

The tube 108 is shown braced against the roof by the jacks 109 and heldby the ring 112, and the undercarriage 100 is shown supported by fourpower jacks 115. The raise driving machine has until now been supportedby a shoulder l 16 inside the tube 108. Now, the machine can beinitiated to start a previously described cutting operation, at firstclimbing on the interior wall of the tube 108, then climbing on the wallof the raise being bored. The contour of the intended raise is indicatedby 118. The rock fragments cut and broken away by the cutter heads 21,22 fall down on a temporarily mounted belt conveyor 117. When themachine has climbed out of the tube 108, the tube 108 can be retracted,the tubes 105, 108 can be tilted into transporting position indicated bythe line 110, and the entire launching vehicle can be moved away.However, the power supply lines which, during the start, passed a window119 in the tube 105 must be disconnected temporarily so as to permit thelaunching vehicle to move away. The steel ring 112, however, is left sothat the vehicle can easily be replaced if it is desired to take downthe machine in which case the machine is operated to climb down into thetube 108.

It is to be understood that the invention is not limited to thedescribed embodiment, but that various modifications may be made withinthe scope of the claims. Instead of the described cutter heads, forinstance, a number of cutter heads in the form of freely rotating rollerbits may be used.

What we claim is:

l. A raise boring machine for producing a raise of circular crosssection, comprising a main frame, a drum member rotatably mounted in themain frame for rotating about the central longitudinal axis of themachine power means for moving the main frame and the anchoring devicelongitudinally relative to each other, a plurality of wall engagingshoes mounted to the main frame so as to be movable radially thereto,means for biasing said shoes against the wall of the raise being bored,linkage means coupled between the main frame and the shoes for exertingoutwardly directed forces to the shoes so as to prevent the shoes andthereby the machine from sliding backwards when the anchoring device isreleased, but permitting the shoes and thereby the main frame to slideforwards when the anchoring device is immobilized and the main frame isbeing advanced.

2. A raise boring machine as claimed in claim 1 in which said shoes onsaid main frame are arranged at the front end of the raise boringmachine; said anchoring device is arranged at the rear end of the raiseboring machine, and power jacks are arranged for moving the rear portionof the main frame relative to the anchoring device in directionstransverse to the longitudinal axis of the raise so as to effectsteering of the raise boring machine.

3. A raise boring machine as claimed in claim 1 in which said cutterheads are rotatably mounted in the drum member, motors are arranged torotate the cutter heads, and the cutter heads have cutters extendingradially from their circular front so that the cutter heads cuttangentially in screw-formed paths upon simultaneous rotation of thecutter heads, rotation of the drum member, and advancing of the mainframe.

4. A raise boring machine as claimed in claim 1 in which said linkagemeans comprise rods which are pivotally connected to the main frame withtheir upper ends and pivotally connected to the shoes with their lowerends so as to suspend the shoes in the main frame, each shoe beingsuspended in two rods whose longitudinal axes intersect at an obtuseangle.

5. A raise boring machine as claimed in claim 4 in which the main frameis provided with means for guiding the shoes radially.

6. A raise boring machine as claimed in claim 4 in which said shoesmounted to said main frame are uniformly angularly spaced in a planetransverse to the raise, and said biasing means are braced between theadjacent shoes to bias the shoes against the wall of the raise.

7. A raise boring machine as claimed in claim 4 in which said biasingmeans comprise a cylinder and a hydraulically actuated piston movabletherein, a spring for extending said piston, and means for supplyinghydraulic fluid to the pressure chamber of said cylinder so as to causeretraction of said pistons and thereby pull the shoes out of engagementwith the wall of the raise.

8. A raise boring machine as claimed in claim 7, in which said anchoringdevice includes a plurality of wall engaging shoes, and a plurality ofhydraulically actuated power jacks arranged to brace said shoes firmlyagainst the wall of the raise so as to immobilize the anchoring devicein the raise when the pressure chambers of the jacks are pressurized byhydraulic fluid.

9. A raise boring machine as claimed in claim 8 in which said pressurechamber of the power jacks for actuating the shoes of the anchoringdevice are connected to a common supply conduit, and said pressurechambers of the cylinder for actuating the shoes of the main frame areconnected to a pilot actuated check valve which is controlled by thepressure in said common supply conduit so as to drain said pressurechambers of the piston and cylinder means when this pressure is below alimit pressure.

10. A raise boring machine as claimed in claim 8 in which said means forsupplying hydraulic fluid to the pressure chamber of said cylindercomprises a pump driven by an electric motor, the pressure chamber ofeach of the power jacks of the anchoring device being connected to oneof a plurality of pressure actuated electric switches, which are biasedto disconnected state, so as to close its associated switch only whenthe pressure in the respective pressure chamber is above a limitpressure, and said electric switches are connected in series in anelectric circuit for actuating said electric motor.

11. A raise boring machine as claimed in claim 10in which said pressurechambers of the power jacks for actuating the shoes of the anchoringdevice are connected to a common supply conduit, and said pressurechambers of the piston and cylinder means for actuating the shoes of themain frame are connected to a pilot actuated check valve which iscontrolled by the pressure in said common supply conduit so as to drainsaid pressure chambers of the piston and cylinder means when thispressure is below a limit pressure.

12. A raise boring machine as claimed in claim 11 in which: saidanchoring device comprises a number of arc-formed shoe units which areangularly spaced uniformly in a plane transverse to the raise, powerjacks are connected between all adjacent ends of said shoe units forpressing the shoe units against the wall of the raise, said main frameis guided by the shoe units of the anchoring device so as to be movableboth longitudinally and radially with respect to each of the shoe units,and said power jacks for effecting steering are arranged to move saidmain frame tangentially with respect to each of said shoe units of theanchoring device, the tangential movements creating simultaneous radialmovements between said main frame and the shoe units.

13. A raise boring machine as claimed in claim 12, in which saidanchoring device has three shoe units, three double-acting power jacksare arranged for effecting steering, the angle between the power jacksfor effecting steering is 60, and each power jack for effecting steeringis firmly connected to either of the main frame and one of the shoeunits, but connected to the other one of said main frame and said shoeunit by means of a sliding connection which permits movement both inlongitudinal and radial directions.

14. A raise boring machine as claimed in claim 13 in which: each of saidsteering jacks has two pressure chambers which are connected to one ofthree direction control valves; each of said direction control valveshas a first position in which movement in one direction of the steeringjack to which it is connected is effected, and a second position inwhich movement in the other direction is effected; each of said steeringjacks is balanced with respect to its piston surfaces; the threesteering jacks are, connected in series to a source of hydraulic fluidthrough said control valve; and a conduit, which includes a controlvalve having an open and a clos ed position, is connected in parallelwith the direction control valve of one of said steering acks;

said one of said steering jacks has half the piston area of each of theother two steering jacks; and said direction control valve of said oneof the steering jacks has also a closed position.

15. A raise boring machine for producing a raise of circular crosssection, comprising a main frame, a drum member rotatably mounted insaid main frame for rotating about a central longitudinal axis of themachine which axis normally coincides with the axis of the raise beingdriven, motor means for rotating said drum member, at least one cutterhead mounted on the drum member for cutting in the face of the raise, aringshaped anchoring device axially movable with respect to said mainframe, power means for advancing the main frame with respect to theanchoring device, and a number of raise wall engaging shoes so mountedon the main frame as to be prevented from sliding rearwards by beingpressed against the wall of the raise when the anchoring device isreleased but permitted to slide forwards on the wall when the main frameis advanced, said anchoring device comprising a number of arcformed shoeunits which are angularly spaced uniformly in a plane transverse to theraise, and power jacks connected between all adjacent ends of the shoeunits for pressing the shoe units against the wall of the raise andthereby immobilizing the anchoring device in the raise.

16. A raise boring machine as claimed in claim 15 in which said shoes onsaid main frame are arranged at the front end of the raise driver, saidanchoring device is arranged at the rear end of the raise driver, andpower jacks are arranged for moving the rear portion of the main framerelative to the anchoring device in directions transverse to thelongitudinal axis of the raise so as to effect steering of the raisedriver.

17. A raise boring machine as claimed in claim 16, in which said mainframe is guided by the shoe units of the anchoring device so as to bemovable both longitudinally and radially with respect to each of theshoe units, but not turnable, and said power jacks for effectingsteering are arranged to move said main frame tangentially with respectto each of said shoe units of the anchoring device, the tangentialmovements creating simultaneous radial movements between said main frameand the shoe units.

1. A raise boring machine for producing a raise of circular crosssection, comprising a main frame, a drum member rotatably mounted in themain frame for rotating about the central longitudinal axis of themachine which axis normally coincides with the axis of the raise beingbored, motor means for rotating the drum member, a plurality of cutterheads mounted on the drum member for cutting in the face of the raise,an anchoring device movable with respect to the main frame and arrangedto be immobilized in the raise, power means for moving the main frameand the anchoring device longitudinally relative to each other, aplurality of wall engaging shoes mounted to the main frame so as to bemovable radially thereto, means for biasing said shoes against the wallof the raise being bored, linkage means coupled between the main frameand the shoes for exerting outwardly directed forces to the shoes so asto prevent the shoes and thereby the machine from sliding backwards whenthe anchoring device is released, but permitting the shoes and therebythe main frame to slide forwards when the anchoring device isimmobilized and the main frame is being advanced.
 2. A raise boringmachine as claimed in claim 1 in which said shoes on said main frame arearranged at the front end of the raise boring machine; said anchoringdevice is arranged at the rear end of the raise boring machine, andpower jacks are arranged for moving the rear portion of the main framerelative to the anchoring device in directions transverse to thelongitudinal axis of the raise so as to effect steering of the raiseboring machine.
 3. A raise boring machine as claimed in claim 1 in whichsaid cutter heads are rotatably mounted in the drum member, motors arearranged to rotate the cutter heads, and the cutter heads have cuttersextending radially from their circular front so that the cutter headscut tangentially in screw-formed paths upon simultaneous rotation of thecutter heads, rotation of the drum member, and advancing of the mainframe.
 4. A raise boring machine as claimed in claim 1 in which saidlinkage means comprise rods which are pivotally connected to the mainframe with their upper ends and pivotally connected to the shoes withtheir lower ends so as to suspend the shoes in the main frame, each shoebeing suspended in two rods whose longitudinal axes intersect at anobtuse angle.
 5. A raise boring machine as claimed in claim 4 in whichthe main frame is provided with means for guiding the shoes radially. 6.A raise boring machine as claimed in claim 4 in which said shoes mountedto said main frame are uniformly angularly spaced in a plane transverseto the raise, and said biasing means are braced between the adjacentshoes to bias the shoes against the wall of the raise.
 7. A raise boringmachine as claimed in claim 4 in which said biasing means comprise acylinder and a hydraulically actuated piston movable therein, a springfor extending said piston, and means for supplying hydraulic fluid tothe pressure chamber of said cylinder so as to cause retraction of saidpistons and thereby pull the shoes out of engagement with the wall ofthe raise.
 8. A raise boring machine as claimed in claim 7, in whichsaid anchoring device includes a plurality of wall engaging shoes, and aplurality of hydraulically actuated power jacks arranged to brace saidshoes firmly against the wall of the raise so as to immobilize theanchoring device in the raise when the pressure chambers of the jacksare pressurized by hydraulic fluid.
 9. A raise boring machine as claimedin claim 8 in which said pressure chamber of the power jacks foractuating the shoes of the anchoring device are connected to a commonsupply conduit, and said pressure chambers of the cylinder for actuatingthe shoes of the main frame are connected to a pilot actuated checkvalve which is controlled by the pressure in said common supply conduitso as to drain said pressure chambers of the piston and cylinder meanswhen this pressure is below a limit pressure.
 10. A raise boring machineas claimed in claim 8 in which said means for supplying hydraulic fluidto the pressure chamber of said cylinder comprises a pump driven by anelectric motor, the pressure chamber of each of the power jacks of theanchoring device being connected to one of a plurality of pressureactuated electric switches, which are biased to disconnected state, soas to close its associated switch only when the pressure in therespective pressure chamber is above a limit pressure, and said electricswitches are connected in series in an electric circuit for actuatingsaid electric motor.
 11. A raise boring machine as claimed in claim 10in which said pressure chambers of the power jacks for actuating theshoes of the anchoring device are connected to a common supply conduit,and said pressure chambers of the piston and cylinder means foractuating the shoes of the main frame are connected to a pilot actuatedcheck valve which is controlled by the pressure in said common supplyconduit so as to drain said pressure chambers of the piston and cylindermeans when this pressure is below a limit pressure.
 12. A raise boringmachine as claimed in claim 11 in which: said anchoring device comprisesa number of arc-formed shoe units which are angularly spaced uniformlyin a plane transverse to the raise, power jacks are connected betweenall adjacent ends of said shoe units for pressing the shoe units againstthe wall of the raise, said main frame is guided by the shoe units ofthe anchoring device so as to be movable both longitudinally andradially with respect to each of the shoe units, and said power jacksfor effecting steering are arranged to move said main frame tangentiallywith respect to each of said shoe units of the anchoring device, thEtangential movements creating simultaneous radial movements between saidmain frame and the shoe units.
 13. A raise boring machine as claimed inclaim 12, in which said anchoring device has three shoe units, threedouble-acting power jacks are arranged for effecting steering, the anglebetween the power jacks for effecting steering is 60*, and each powerjack for effecting steering is firmly connected to either of the mainframe and one of the shoe units, but connected to the other one of saidmain frame and said shoe unit by means of a sliding connection whichpermits movement both in longitudinal and radial directions.
 14. A raiseboring machine as claimed in claim 13 in which: each of said steeringjacks has two pressure chambers which are connected to one of threedirection control valves; each of said direction control valves has afirst position in which movement in one direction of the steering jackto which it is connected is effected, and a second position in whichmovement in the other direction is effected; each of said steering jacksis balanced with respect to its piston surfaces; the three steeringjacks are, connected in series to a source of hydraulic fluid throughsaid control valve; and a conduit, which includes a control valve havingan open and a closed position, is connected in parallel with thedirection control valve of one of said steering jacks; said one of saidsteering jacks has half the piston area of each of the other twosteering jacks; and said direction control valve of said one of thesteering jacks has also a closed position.
 15. A raise boring machinefor producing a raise of circular cross section, comprising a mainframe, a drum member rotatably mounted in said main frame for rotatingabout a central longitudinal axis of the machine which axis normallycoincides with the axis of the raise being driven, motor means forrotating said drum member, at least one cutter head mounted on the drummember for cutting in the face of the raise, a ring-shaped anchoringdevice axially movable with respect to said main frame, power means foradvancing the main frame with respect to the anchoring device, and anumber of raise wall engaging shoes so mounted on the main frame as tobe prevented from sliding rearwards by being pressed against the wall ofthe raise when the anchoring device is released but permitted to slideforwards on the wall when the main frame is advanced, said anchoringdevice comprising a number of arc-formed shoe units which are angularlyspaced uniformly in a plane transverse to the raise, and power jacksconnected between all adjacent ends of the shoe units for pressing theshoe units against the wall of the raise and thereby immobilizing theanchoring device in the raise.
 16. A raise boring machine as claimed inclaim 15 in which said shoes on said main frame are arranged at thefront end of the raise driver, said anchoring device is arranged at therear end of the raise driver, and power jacks are arranged for movingthe rear portion of the main frame relative to the anchoring device indirections transverse to the longitudinal axis of the raise so as toeffect steering of the raise driver.
 17. A raise boring machine asclaimed in claim 16, in which said main frame is guided by the shoeunits of the anchoring device so as to be movable both longitudinallyand radially with respect to each of the shoe units, but not turnable,and said power jacks for effecting steering are arranged to move saidmain frame tangentially with respect to each of said shoe units of theanchoring device, the tangential movements creating simultaneous radialmovements between said main frame and the shoe units.